diff --git a/ncsid/src/common_defs.h b/ncsid/src/common_defs.h
index 70f51b8..757eb52 100644
--- a/ncsid/src/common_defs.h
+++ b/ncsid/src/common_defs.h
@@ -1,3 +1,19 @@
+/*
+ * Copyright 2021 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 #pragma once
 
 #define RETURN_IF_ERROR(expr, msg)                                             \